1. Field of the Invention
The present invention relates to a fixing apparatus applied to an image forming apparatus such as a copying machine, a printer and the like, and more particularly, it relates to a blade device applied to such a fixing apparatus.
2. Related Background Art
Generally, in conventional fixing apparatuses, while a recording medium bearing a non-fixed image thereon is being passed through a nip between a fixing member and a pressurizing member which are pressure-contacted with each other, the recording medium is thermally treated by heating means for generating heat by an electric power supplied from a commercial power source.
Residual matters may occur on the fixing member and the pressurizing member, and, particularly, the residual matters are apt to occur on the fixing member which are pressure-contacted with a non-fixed image bearing surface of a transfer sheet (recording medium).
To cope with this, in the past, there has been proposed a fixing apparatus having a molding lubricant coating means for coating a molding lubricant capable of improving mold releasing ability of the residual matters from the fixing member on at least one of the fixing member and the pressurizing member, and a coating amount regulating member for regulating a coating amount of the molding lubricant on the fixing member thereby to improve the mold releasing ability of the residual matters from the fixing member.
In the past, as the coating amount regulating member, for example, as shown in FIG. 9, a regulating blade 100 is already known and has been put to practical use. Incidentally, FIG. 9 is a front view showing a schematic construction of the regulating blade 100.
The regulating blade 100 comprises a thin plate-shaped support member 101 consisting essentially of metal such as iron, and a rubbing member 102 for regulating an amount of molding lubricant on the fixing member by rubbing the fixing member.
In the support member 101, at a side on which the rubbing member contacts with the fixing member, i.e., at a rubbing member 102 side end, along a direction perpendicular to a longitudinal direction of the regulating blade 100, widths w (for supporting the rubbing member 102) of both lateral end sections 101A are substantially the same as a width w (for supporting the rubbing member 102) of a central section 101B.
Further, the support member 101 has one end (in the direction perpendicular to the longitudinal direction) supported by a body of the fixing apparatus and the other end (in the direction perpendicular to the longitudinal direction) secured to the rubbing member 102, so that the support member 101 serves to slidingly contact the rubbing member 102 to the fixing member by applying stress generated by flexion of the support member 101 itself to the rubbing member 102.
In the rubbing member 102, at an end opposite to a side secured to the support member 101, both lateral end sections 102A are more protruded than a central section 102B.
That is to say, by slidingly contacting both lateral end sections 102A (having a free length LB) and the central section 102B (having a free length LC) to the fixing member by the support member 101, excessive molding lubricant is removed from the fixing member and both lateral end portions 102 of the rubbing member 102 can prevent the molding lubricant flowed along an edge of the rubbing member 102 in the longitudinal direction from leaking.
Thus, in the conventional art, the rubbing member 102 is slidingly contacted to the fixing member by the stress generated by the flexion of the support member 101 so that the coating amount of the molding lubricant on the fixing member is regulated by removing the excessive molding lubricant from the fixing member while slidingly contacting the rubbing member 102 to the fixing member.
However, in the regulating blade 100, the widths w of the both lateral end sections 101A of the support member 101 are substantially the same as the width w of the central section 101B.
Thus, if the rubbing member 102 is intended to abut against the fixing member, even when the central section 102B of the rubbing member 102 abuts against the fixing member, sections 102C adjacent to both lateral end sections 102A are floating from the fixing member by the influence of the both lateral edge sections 102A.
Therefore, in order to also make the sections 102C abut against the fixing member properly, a force for bending the both lateral end sections 102A is further required. However, due to the presence of such a force, the central section 102B already abutting against the fixing member is subjected to a further force.
As a result, a sliding contact force between the central section of the rubbing member and the fixing member is increased, with the result that the rubbing member is apt to be worn and the service life of the rubbing member is shortened.